Orbitally driven grinding apparatus

ABSTRACT

A turbine driving means for the spindle of an orbital grinding machine. A standard air turbine is fixed to the spindle for following the orbital path and maintaining a given alignment and the grinding tool is positioned on the output shaft of the turbine.

O United States Patent [15) 3,641,710

Heinelt 1 Feb. 15, 1972 [54] ORBITALLY DRIVEN GRINDING 2,608,807 9/1952 Nilsen et al. ..51/90 X APPARATUS 2,648,939 8/1953 Zelik ..51/90 X [72] Inventor: Roland Hemelt, Munich, Germany Primary Examiner ldester M- Swingle [73] Assignee: Friedrich Deckel Prazisions Mechanik & Att0rneyWoodhams, Blanchard and Flynn Maschinenbau, Munich, Germany 22 Filed: Oct. 6, 1969 [57] ABSTRACT A turbine driving means for the spindle of an orbital grinding [21] Appl' 863787 machine, A standard air turbine is fixed to the spindle for fol- [52] US. Cl ..5l/90, 5 l/ 1 34.5 F lowing the orbital path and maintaining a given alignment and [51] Int. Cl ..B24b 5/00 the grinding tool is positioned on the output shaft of the tur- [58] Field of Search ..5l/90, 120, 134.5 F, 134.5 R, bine.

[56] References Cited UNITED STATES PATENTS 6 Claims, 1 Drawing Figure 2,357,109 8/1944 Heath ..51/90 i/m M. l

I r i 2o 1 l LL 22 i I 32 \v p, 2b-

ORBITALLY DRIVEN GRINDING APPARATUS The invention relates to a grinding machine having an orbital rotating grinding spindle which is driven by an air turbine. In such a machine, the supplying of pressurized air to a casing, which is provided with the nozzles to direct the pressurized air onto the turbine blades, creates a problem in that said casing rotates but the air conduits cannot. Attempts to remedy this problem result in special constructions for orbital rotating air turbines which differ considerably from, and are more expensive than, turbines whose housings do not need to rotate.

It is the purpose of the invention to make it possible to use the above-mentioned standard, relatively simple and inexpensive, turbines also in those cases where an orbital movement for the turbine shaft is required. This is done according to the invention by mounting a standard air turbine, including the housing containing the nozzles, at the front side of an orbital shaft and supporting said shaft for rotation about its own axis. In this way, the turbine housing is no longer required during its orbital movement to rotate also about its own axis and the compressed air connections can remain in a single orientation or alignment.

If the grinding machine is already provided with an electrically drivable grinding spindle the projecting shaft end of which has a receiving means for the grinding tools, said grinding spindle is advantageously used as a shaft supported for rotation about its own axis and the housing of the turbine is provided with a shaft fitting into the work tool receiving means. The electrically driven grinding spindle is then used, as previously, for the lower range of rotational speed, while for extremely high rotational speeds of the work tool the electrical drive is switched off and the air turbine inserted into the grinding spindle is used.

Further characteristics of the invention can be understood from the description of one exemplary embodiment in connection with the drawing in which is illustrated in a cross-sectional view an electrically drivable orbital grinding spindle with an air turbine inserted thereinto.

At a machine tool spindle of which the drawing indicates only the axis 10, a grinding motor 12 is secured radially movably to the axis 10. It contains a grinding spindle 18 which is supported rotatably on roller bearings 14 and 16 and which supports the rotor 20 of the motor and has a threaded opening 22 at its lower end. The grinding spindle 18 rotates about its own axis and also about the axis 10 of the machine spindle. The threaded opening 22 is used as receiver for the grinding tool and is used in this manner whenever the rotational speeds obtainable with the grinding motor are sufficient.

Where higher rotational speeds of the grinding tool are needed, an air turbine 24 is inserted into the grinding spindle and the turbine spindle 26 of said air turbine 24 supports the grinding tool 28. The housing of the turbine 24 is for this purpose provided with a shaft 30 which fits into the threaded opening 22. The turbine spindle 26 is, in a known and therefore not illustrated manner, supported in the turbine housing by means of roller bearings or pressurized air bearings and supports a runner provided with vanes. Nozzles provided in the housing direct compressed air to the vanes of said runner. The compressed air is supplied through a conduit 32 attached to the turbine housing, while the exhaust air is discharged through a conduit 34. Flexible conduit lines are connected to the conduits 32 and 34.

Upon orbiting the motor 12 about the axis 10, the grinding spindle I8 and the turbine 24 inserted in said grinding spindle can rotate freely while the air conduits 32 and 34 maintain their orientation or alignment.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a machine tool having a rotatable spindle, the combination comprising:

frame means securable to said spindle and rotatable therewith;

first driving means secured to said frame means. said first driving means having a first selectively rotatable output shaft radially offset from said spindle and first coupling means on the free end of said first rotatable output shaft, said first rotatable output shaft being drivable at a first rotational speed; and

second driving means having second coupling means adapted to be releasably coupled to said first coupling means, said second driving means having a second rotatable output shaft and being adapted to drive said second rotatably driven output shaft at a second rotational speed and a tool having means thereon adapted to releasably secure said tool to one of said first coupling means and said second rotatable output shaft;

whereby said spindle may be rotated to move said first rotatable output shaft in an orbital path and said first driving means may be selectively nonoperable and said second driving means may be operated at said second rotational speed to drive said tool at said second rotational speed and in said orbital path and, in the alternative, said second coupling means on said second driving means may be released from said first coupling means on said first selectively rotatable output shaft so that said tool may be secured to said first coupling means and driven for rotation by said first driving means at said first rotational speed and in said orbital path.

2. A machine tool according to claim I, wherein said second rotational speed is substantially greater than said first rotational speed.

3. A machine tool according to claim 1, wherein said first driving means is an electric motor having a stator fixed to said frame means and a rotor secured to said first rotatable output shaft.

4. A machine tool according to claim 3, wherein said second driving means comprises a pneumatic motor having housing means with said second coupling means thereon releasably secured directly to said first coupling means;

including pneumatic supply conduit means secured to said housing means for supplying pneumatic fluid thereto; and wherein said second rotatable output shaft is a turbine member of said pneumatic motor.

5. A machine tool according to claim 1, wherein said frame means includes means for adjustably securing said frame means to said spindle to vary the radius of said orbital path.

6. In combination with a machine tool having a selectively rotatable spindle movable through an orbital path, said spindle having tool-receiving means thereon, pneumatic driving means having housing means with means thereon adapted to releasably secure said housing means directly to said toolreceiving means on said orbitally movable spindle, said releasable securement preventing a relative rotational movement between said housing means and said spindle, said housing means having pneumatic supply conduit means secured thereto for supplying pneumatic fluid to said housing means and a high-speed turbine rotatably supported in said housing means and responsive to the supply of pneumatic fluid to said housing means and tool holding means secured to said turbine for holding a tool thereon and for rotation therewith. 

1. In a machine tool having a rotatable spindle, the combination comprising: frame means securable to said spindle and rotatable therewith; first driving means secured to said frame means, said first driving means having a first selectively rotatable output shaft radially offset from said spindle and first coupling means on the free end of said first rotatable output shaft, said first rotatable output shaft being drivable at a first rotational speed; and second driving means having second coupling means adapted to be releasably coupled to said first coupling means, said second driving means having a second rotatable output shaft and being adapted to drive said second rotatably driven output shaft at a second rotational speed and a tool having means thereon adapted to releasably secure said tool to one of said first coupling means and said second rotatable output shaft; whereby said spindle may be rotated to move said first rotatable output shaft in an orbital path and said first driving means may be selectively nonoperable and said second driving means may be operated at said second rotational speed to drive said tool at said second rotational speed and in said orbital path and, in the alternative, said second coupling means on said second driving means may be released from said first coupling means on said first selectively rotatable output shaft so that said tool may be secured to said first coupling means and driven for rotation by said first driving means at said first rotational speed and in said orbital path.
 2. A machine tool according to claim 1, wherein said second rotational speed is substantially greater than said first rotational speed.
 3. A machine tool according to claim 1, wherein said first driving means is an electric motor having a stator fixed to said frame means and a rotor secured to said first rotatable output shaft.
 4. A machine tool according to claim 3, wherein said second driving means comprises a pneumatic motor having housing means with said second coupling means thereon releasably secured directly to said first coupling means; including pneumatic supply conduit means secured to said housing means for supplying pneumatic fluid thereto; and wherein said second rotatable output shaft is a turbine member of said pneumatic motor.
 5. A machine tool according to claim 1, wherein said frame means includes means for adjustably securing said frame means to said spindle to vary the radius of said orbital path.
 6. In combination with a machine tool having a selectively rotatable spindle movable through an orbital path, said spindle having tool-receiving means thereon, pneumatic driving means having housing means with means thereon adapted to releasably secure said housing means directly to said tool-receiving means on said orbitally movable spindle, said releasable securement preventing a relative rotational movement between said housing means and said spindle, said housing means having pneumatic supply conduit means secured thereto for supplying pneumatic fluid to said housing means and a high-speed turbine rotatably supported in said housing means and responsive to the supply of pneumatic fluid to said housing means and tool holding means secured to said turbine for holding a tool thereon and for rotation therewith. 